debugfs: fix set_field's handling of timestamps

How timestamps are encoded in inodes and superblocks are different.
Unfortunately, commit ca8bc9240a00 which added post-2038 timestamps
was (a) overwriting adjacent superblock fields and/or attempting
unaligned writes to a 8-bit field from a 32-bit pointer, and (b) using
the incorrect encoding for timestamps stored in inodes.  Fix both of
these issues, which were found thanks to UBSAN.

Fixes: ca8bc9240a00 ("Add post-2038 timestamp support to e2fsprogs")
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

1 files changed, 49 insertions, 17 deletions

diff --git a/debugfs/set_fields.c b/debugfs/set_fields.c
index 6755f8802..4980a63d8 100644
--- a/debugfs/set_fields.c
+++ b/debugfs/set_fields.c
@@ -71,7 +71,9 @@ static errcode_t parse_string(struct field_set_info *info, char *field, char *ar
 static errcode_t parse_uuid(struct field_set_info *info, char *field, char *arg);
 static errcode_t parse_hashalg(struct field_set_info *info, char *field, char *arg);
 static errcode_t parse_encoding(struct field_set_info *info, char *field, char *arg);
-static errcode_t parse_time(struct field_set_info *info, char *field, char *arg);
+static errcode_t parse_sb_time(struct field_set_info *info, char *field, char *arg);
+static errcode_t parse_ino_time(struct field_set_info *info, char *field, char *arg);
+
 static errcode_t parse_bmap(struct field_set_info *info, char *field, char *arg);
 static errcode_t parse_gd_csum(struct field_set_info *info, char *field, char *arg);
 static errcode_t parse_inode_csum(struct field_set_info *info, char *field,
@@ -99,8 +101,8 @@ static struct field_set_info super_fields[] = {
 	{ "blocks_per_group", &set_sb.s_blocks_per_group, NULL, 4, parse_uint },
 	{ "clusters_per_group", &set_sb.s_clusters_per_group, NULL, 4, parse_uint },
 	{ "inodes_per_group", &set_sb.s_inodes_per_group, NULL, 4, parse_uint },
-	{ "mtime", &set_sb.s_mtime, &set_sb.s_mtime_hi, 5, parse_time },
-	{ "wtime", &set_sb.s_wtime, &set_sb.s_wtime_hi, 5, parse_time },
+	{ "mtime", &set_sb.s_mtime, &set_sb.s_mtime_hi, 5, parse_sb_time },
+	{ "wtime", &set_sb.s_wtime, &set_sb.s_wtime_hi, 5, parse_sb_time },
 	{ "mnt_count", &set_sb.s_mnt_count, NULL, 2, parse_uint },
 	{ "max_mnt_count", &set_sb.s_max_mnt_count, NULL, 2, parse_int },
 	/* s_magic */
@@ -108,7 +110,7 @@ static struct field_set_info super_fields[] = {
 	{ "errors", &set_sb.s_errors, NULL, 2, parse_uint },
 	{ "minor_rev_level", &set_sb.s_minor_rev_level, NULL, 2, parse_uint },
 	{ "lastcheck", &set_sb.s_lastcheck, &set_sb.s_lastcheck_hi, 5,
-		parse_time },
+		parse_sb_time },
 	{ "checkinterval", &set_sb.s_checkinterval, NULL, 4, parse_uint },
 	{ "creator_os", &set_sb.s_creator_os, NULL, 4, parse_uint },
 	{ "rev_level", &set_sb.s_rev_level, NULL, 4, parse_uint },
@@ -141,7 +143,7 @@ static struct field_set_info super_fields[] = {
 	{ "default_mount_opts", &set_sb.s_default_mount_opts, NULL, 4, parse_uint },
 	{ "first_meta_bg", &set_sb.s_first_meta_bg, NULL, 4, parse_uint },
 	{ "mkfs_time", &set_sb.s_mkfs_time, &set_sb.s_mkfs_time_hi, 5,
-		parse_time },
+		parse_sb_time },
 	{ "jnl_blocks", &set_sb.s_jnl_blocks[0], NULL, 4, parse_uint, FLAG_ARRAY,
 	  17 },
 	{ "min_extra_isize", &set_sb.s_min_extra_isize, NULL, 2, parse_uint },
@@ -170,13 +172,13 @@ static struct field_set_info super_fields[] = {
 	{ "encryption_level", &set_sb.s_encryption_level, NULL, 1, parse_uint },
 	{ "error_count", &set_sb.s_error_count, NULL, 4, parse_uint },
 	{ "first_error_time", &set_sb.s_first_error_time,
-		&set_sb.s_first_error_time_hi, 5, parse_time },
+		&set_sb.s_first_error_time_hi, 5, parse_sb_time },
 	{ "first_error_ino", &set_sb.s_first_error_ino, NULL, 4, parse_uint },
 	{ "first_error_block", &set_sb.s_first_error_block, NULL, 8, parse_uint },
 	{ "first_error_func", &set_sb.s_first_error_func, NULL, 32, parse_string },
 	{ "first_error_line", &set_sb.s_first_error_line, NULL, 4, parse_uint },
 	{ "last_error_time", &set_sb.s_last_error_time,
-		&set_sb.s_last_error_time_hi, 5, parse_time },
+		&set_sb.s_last_error_time_hi, 5, parse_sb_time },
 	{ "last_error_ino", &set_sb.s_last_error_ino, NULL, 4, parse_uint },
 	{ "last_error_block", &set_sb.s_last_error_block, NULL, 8, parse_uint },
 	{ "last_error_func", &set_sb.s_last_error_func, NULL, 32, parse_string },
@@ -197,13 +199,13 @@ static struct field_set_info inode_fields[] = {
 		2, parse_uint },
 	{ "size", &set_inode.i_size, &set_inode.i_size_high, 4, parse_uint },
 	{ "atime", &set_inode.i_atime, &set_inode.i_atime_extra,
-		4, parse_time },
+		4, parse_ino_time },
 	{ "ctime", &set_inode.i_ctime, &set_inode.i_ctime_extra,
-		4, parse_time },
+		4, parse_ino_time },
 	{ "mtime", &set_inode.i_mtime, &set_inode.i_mtime_extra,
-		4, parse_time },
+		4, parse_ino_time },
 	{ "dtime", &set_inode.i_dtime, NULL,
-		4, parse_time },
+		4, parse_ino_time },
 	{ "gid", &set_inode.i_gid, &set_inode.osd2.linux2.l_i_gid_high,
 		2, parse_uint },
 	{ "links_count", &set_inode.i_links_count, NULL, 2, parse_uint },
@@ -240,7 +242,7 @@ static struct field_set_info inode_fields[] = {
 	{ "atime_extra", &set_inode.i_atime_extra, NULL,
 		4, parse_uint, FLAG_ALIAS },
 	{ "crtime", &set_inode.i_crtime, &set_inode.i_crtime_extra,
-		4, parse_time },
+		4, parse_ino_time },
 	{ "crtime_extra", &set_inode.i_crtime_extra, NULL,
 		4, parse_uint, FLAG_ALIAS },
 	{ "projid", &set_inode.i_projid, NULL, 4, parse_uint },
@@ -581,18 +583,19 @@ static errcode_t parse_string(struct field_set_info *info,
 	return 0;
 }
 
-static errcode_t parse_time(struct field_set_info *info,
-			    char *field, char *arg)
+static errcode_t parse_sb_time(struct field_set_info *info,
+			       char *field, char *arg)
 {
 	__s64		t;
 	__u32		t_low, t_high;
-	__u32		*ptr_low, *ptr_high;
+	__u32		*ptr_low;
+	__u8		*ptr_high;
 
 	if (check_suffix(field))
 		return parse_uint(info, field, arg);
 
 	ptr_low  = (__u32 *) info->ptr;
-	ptr_high = (__u32 *) info->ptr2;
+	ptr_high = (__u8 *) info->ptr2;
 
 	t = string_to_time(arg);
 
@@ -609,6 +612,34 @@ static errcode_t parse_time(struct field_set_info *info,
 	return 0;
 }
 
+static errcode_t parse_ino_time(struct field_set_info *info,
+			       char *field, char *arg)
+{
+	__s64		t;
+	__u32		t_low, t_high;
+	__u32		*ptr_low, *ptr_high;
+
+	if (check_suffix(field))
+		return parse_uint(info, field, arg);
+
+	ptr_low  = (__u32 *) info->ptr;
+	ptr_high = (__u32 *) info->ptr2;
+
+	t = string_to_time(arg);
+
+	if (t == -1) {
+		fprintf(stderr, "Couldn't parse '%s' for field %s.\n",
+			arg, info->name);
+		return EINVAL;
+	}
+	t_low = (__u32) t;
+	t_high = __encode_extra_time(t, 0);
+	*ptr_low = t_low;
+	if (ptr_high)
+		*ptr_high = t_high;
+	return 0;
+}
+
 static errcode_t parse_uuid(struct field_set_info *info,
 			    char *field EXT2FS_ATTR((unused)), char *arg)
 {
@@ -790,7 +821,8 @@ static void print_possible_fields(struct field_set_info *fields)
 			type = "UUID";
 		else if (ss->func == parse_hashalg)
 			type = "hash algorithm";
-		else if (ss->func == parse_time)
+		else if ((ss->func == parse_sb_time) ||
+			 (ss->func == parse_ino_time))
 			type = "date/time";
 		else if (ss->func == parse_bmap)
 			type = "set physical->logical block map";